1. Field of Invention
The invention relates to a filter part for fluid lines, for use especially in filling nipples, non-return valves, pressure regulators, cylinder valves, filling couplings, switching valves, break-off safety devices, quick couplings and also as a separate filter part.
2. Description of the Related Art
The invention relates to a filter part for fluid lines, preferably high-pressure lines with pressures in the range of 150 to 900 bar, preferably in the range of 200 to 350 bar, more preferably in the range of 700 to 875 bar, for use especially in filling nipples, non-return valves, pressure regulators, cylinder valves, filling couplings, switching valves, break-off safety devices, quick couplings and also as a separate filter part. The filter part comprises a base body and at least one fluid passage opening, wherein the base body and the fluid passage opening are covered by at least one filter element. The invention further relates to a method for producing a filter part with a base body and a filter element, especially in form of a screen filter which is also known as a filter mesh.
A filter part, especially for use in filling nipples, comprising a base body and at least one fluid passage opening covered by a filter element, is known from WO 02/00322 A1. The filter element is provided by a narrowly wound spring wire in a filter parts according to WO 02/00322 A1. The filter part known from WO 02/00322 A1 is to provide a substantially simple and strong filter part for fluid lines which is suitable for use in filling nipples for fluids, especially gaseous media and natural gas in particular, with a filling pressure of 200 bar. In particular, WO 02/00322 A1 intends to avoid the disadvantages of filter parts in which the filter elements are arranged as a braided fabric or a metal braiding, where the filter elements are perforated plates or sintered bodies of defined porosity. WO 02/00322 A1 describes the use of filter elements, especially metal fabrics and metal braiding, as disadvantageous for the use in filling nipples with filling pressures of up to 875 bar and more, since they are sensitive to compressive loading or alternating loads which can lead to material fatigue. The filter part known from WO 02/00322 A1 is designed for use with filling pressures of 200 bar substantially for natural gas, but only within limits for high pressures in the range of 700 to 875 bar, which is necessary for use of hydrogen in combination with very high filter fineness.
A valve which is controllable by means of a pressure of a fluid is known from DE 1016138 A1, in which a filter fabric not designated in closer detail is provided in front of the conical closing body.
U.S. Pat. No. 5,922,291 shows a reformer with a particle filter, wherein the particle filter is inserted into the reformate gas feed line and is arranged to be removable. This filter is configured in such a way that it is capable of retaining very fine dust particles which are carried by the reformate gas flow. A filter fabric is provided on the gas outlet which is arranged as a non-woven fibre material.
An apparatus for removing substances from oil is known from U.S. Pat. No. 5,074,381. The aperture comprises a polyester mesh as the filter screen, with openings of approximately 105 μm, so that particles with a size >0.0127 cm are retained, while the oil is pressed through the polyester mesh.
U.S. Pat. No. 4,442,003 shows a filter arrangement which is used especially for the use of liquid dye supply systems. The filter arrangement is used to keep foreign particles away from the spray nozzle. The filter according to U.S. Pat. No. 4,442,003 comprises an exchangeable filter which is arranged as a filter screen. U.S. Pat. No. 4,442,003 does not provide information on the filter mesh width and the filter configuration.
U.S. Pat. No. 2,068,858 discloses a filter nipple which is introduced into a gas line, in which the high-pressure gas is supplied to the gas consumer. The filter known from U.S. Pat. No. 2,068,858 comprises a screen with a different shape and a different mesh width. U.S. Pat. No. 2,068,858 does not provide any information on the gas pressure and the mesh width.
U.S. Pat. No. 1,644,121 shows a screen which is preferably used in a pump, especially a centrifugal pump.
None of the aforementioned citations discloses how a filter device for high pressures of up to 900 bar and more can be designed which is suitable for use with hydrogen and simultaneously offers a very high filter fineness.